@keyframes spin {
    to { transform: rotate(.5turn); }
}

@keyframes bg {
    50% { background: #655; }
}


svg.ProgressCircle {
    width: 100px; height: 100px;
    transform: rotate(-90deg);
    background: #aaa;
    border-radius: 50%;
}

circle.ProgressCircle {
    fill: #aaa;
    stroke: #aaa;
    stroke-width: 32;
    animation: fillup 5s linear ease-in-out;
}